mac80211: implement uAPSD

Add uAPSD support to mac80211. This is probably not
possible with all devices, so advertising it with
the cfg80211 flag will be left up to drivers that
want it.

Due to my previous patches it is now a fairly
straight-forward extension. Drivers need to have
accurate TX status reporting for the EOSP frame.
For drivers that buffer themselves, the provided
APIs allow releasing the right number of frames,
but then drivers need to set EOSP and more-data
themselves. This is documented in more detail in
the new code itself.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlegacy/iwl-4965-tx.c

@@ -335,7 +335,7 @@ int iwl4965_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 		sta_priv = (void *)sta->drv_priv;
 
 	if (sta_priv && sta_priv->asleep &&
-	    (info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE)) {
+	    (info->flags & IEEE80211_TX_CTL_POLL_RESPONSE)) {
 		/*
 		 * This sends an asynchronous command to the device,
 		 * but we can rely on it being processed before the

drivers/net/wireless/iwlwifi/iwl-agn-tx.c

@@ -300,7 +300,7 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 		sta_priv = (void *)info->control.sta->drv_priv;
 
 	if (sta_priv && sta_priv->asleep &&
-	    (info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE)) {
+	    (info->flags & IEEE80211_TX_CTL_POLL_RESPONSE)) {
 		/*
 		 * This sends an asynchronous command to the device,
 		 * but we can rely on it being processed before the

drivers/net/wireless/p54/txrx.c

@@ -689,7 +689,7 @@ static void p54_tx_80211_header(struct p54_common *priv, struct sk_buff *skb,
 	if (!(info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ))
 		*flags |= P54_HDR_FLAG_DATA_OUT_SEQNR;
 
-	if (info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE)
+	if (info->flags & IEEE80211_TX_CTL_POLL_RESPONSE)
 		*flags |= P54_HDR_FLAG_DATA_OUT_NOCANCEL;
 
 	if (info->flags & IEEE80211_TX_CTL_CLEAR_PS_FILT)

include/net/mac80211.h

@@ -339,9 +339,9 @@ struct ieee80211_bss_conf {
  *	used to indicate that a frame was already retried due to PS
  * @IEEE80211_TX_INTFL_DONT_ENCRYPT: completely internal to mac80211,
  *	used to indicate frame should not be encrypted
- * @IEEE80211_TX_CTL_PSPOLL_RESPONSE: (internal?)
- *	This frame is a response to a PS-poll frame and should be sent
- *	although the station is in powersave mode.
+ * @IEEE80211_TX_CTL_POLL_RESPONSE: This frame is a response to a poll
+ *	frame (PS-Poll or uAPSD) and should be sent although the station
+ *	is in powersave mode.
  * @IEEE80211_TX_CTL_MORE_FRAMES: More frames will be passed to the
  *	transmit function after the current frame, this can be used
  *	by drivers to kick the DMA queue only if unset or when the
@@ -367,6 +367,10 @@ struct ieee80211_bss_conf {
  * @IEEE80211_TX_CTL_NO_CCK_RATE: This frame will be sent at non CCK rate.
  *	This flag is actually used for management frame especially for P2P
  *	frames not being sent at CCK rate in 2GHz band.
+ * @IEEE80211_TX_STATUS_EOSP: This packet marks the end of service period,
+ *	when its status is reported the service period ends. For frames in
+ *	an SP that mac80211 transmits, it is already set; for driver frames
+ *	the driver may set this flag.
  *
  * Note: If you have to add new flags to the enumeration, then don't
  *	 forget to update %IEEE80211_TX_TEMPORARY_FLAGS when necessary.
@@ -388,7 +392,7 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_INTFL_NEED_TXPROCESSING	= BIT(14),
 	IEEE80211_TX_INTFL_RETRIED		= BIT(15),
 	IEEE80211_TX_INTFL_DONT_ENCRYPT		= BIT(16),
-	IEEE80211_TX_CTL_PSPOLL_RESPONSE	= BIT(17),
+	IEEE80211_TX_CTL_POLL_RESPONSE		= BIT(17),
 	IEEE80211_TX_CTL_MORE_FRAMES		= BIT(18),
 	IEEE80211_TX_INTFL_RETRANSMISSION	= BIT(19),
 	IEEE80211_TX_INTFL_HAS_RADIOTAP		= BIT(20),
@@ -398,6 +402,7 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTL_TX_OFFCHAN		= BIT(25),
 	IEEE80211_TX_INTFL_TKIP_MIC_FAILURE	= BIT(26),
 	IEEE80211_TX_CTL_NO_CCK_RATE		= BIT(27),
+	IEEE80211_TX_STATUS_EOSP		= BIT(28),
 };
 
 #define IEEE80211_TX_CTL_STBC_SHIFT		23
@@ -411,9 +416,9 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTL_SEND_AFTER_DTIM | IEEE80211_TX_CTL_AMPDU |	      \
 	IEEE80211_TX_STAT_TX_FILTERED |	IEEE80211_TX_STAT_ACK |		      \
 	IEEE80211_TX_STAT_AMPDU | IEEE80211_TX_STAT_AMPDU_NO_BACK |	      \
-	IEEE80211_TX_CTL_RATE_CTRL_PROBE | IEEE80211_TX_CTL_PSPOLL_RESPONSE | \
+	IEEE80211_TX_CTL_RATE_CTRL_PROBE | IEEE80211_TX_CTL_POLL_RESPONSE |   \
 	IEEE80211_TX_CTL_MORE_FRAMES | IEEE80211_TX_CTL_LDPC |		      \
-	IEEE80211_TX_CTL_STBC)
+	IEEE80211_TX_CTL_STBC | IEEE80211_TX_STATUS_EOSP)
 
 /**
  * enum mac80211_rate_control_flags - per-rate flags set by the
@@ -1624,9 +1629,12 @@ enum ieee80211_tx_sync_type {
 /**
  * enum ieee80211_frame_release_type - frame release reason
  * @IEEE80211_FRAME_RELEASE_PSPOLL: frame released for PS-Poll
+ * @IEEE80211_FRAME_RELEASE_UAPSD: frame(s) released due to
+ *	frame received on trigger-enabled AC
  */
 enum ieee80211_frame_release_type {
 	IEEE80211_FRAME_RELEASE_PSPOLL,
+	IEEE80211_FRAME_RELEASE_UAPSD,
 };
 
 /**
@@ -1954,7 +1962,9 @@ enum ieee80211_frame_release_type {
  *	In the case this is used for uAPSD, the @num_frames parameter may be
  *	bigger than one, but the driver may send fewer frames (it must send
  *	at least one, however). In this case it is also responsible for
- *	setting the EOSP flag in the QoS header of the frames.
+ *	setting the EOSP flag in the QoS header of the frames. Also, when the
+ *	service period ends, the driver must set %IEEE80211_TX_STATUS_EOSP
+ *	on the last frame in the SP.
  *	This callback must be atomic.
  */
 struct ieee80211_ops {

net/mac80211/rx.c

@@ -1162,6 +1162,79 @@ int ieee80211_sta_ps_transition(struct ieee80211_sta *sta, bool start)
 }
 EXPORT_SYMBOL(ieee80211_sta_ps_transition);
 
+static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_uapsd_and_pspoll(struct ieee80211_rx_data *rx)
+{
+	struct ieee80211_sub_if_data *sdata = rx->sdata;
+	struct ieee80211_hdr *hdr = (void *)rx->skb->data;
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
+	int tid, ac;
+
+	if (!rx->sta || !(status->rx_flags & IEEE80211_RX_RA_MATCH))
+		return RX_CONTINUE;
+
+	if (sdata->vif.type != NL80211_IFTYPE_AP &&
+	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
+		return RX_CONTINUE;
+
+	/*
+	 * The device handles station powersave, so don't do anything about
+	 * uAPSD and PS-Poll frames (the latter shouldn't even come up from
+	 * it to mac80211 since they're handled.)
+	 */
+	if (sdata->local->hw.flags & IEEE80211_HW_AP_LINK_PS)
+		return RX_CONTINUE;
+
+	/*
+	 * Don't do anything if the station isn't already asleep. In
+	 * the uAPSD case, the station will probably be marked asleep,
+	 * in the PS-Poll case the station must be confused ...
+	 */
+	if (!test_sta_flags(rx->sta, WLAN_STA_PS_STA))
+		return RX_CONTINUE;
+
+	if (unlikely(ieee80211_is_pspoll(hdr->frame_control))) {
+		if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
+			ieee80211_sta_ps_deliver_poll_response(rx->sta);
+		else
+			set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
+
+		/* Free PS Poll skb here instead of returning RX_DROP that would
+		 * count as an dropped frame. */
+		dev_kfree_skb(rx->skb);
+
+		return RX_QUEUED;
+	} else if (!ieee80211_has_morefrags(hdr->frame_control) &&
+		   !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
+		   ieee80211_has_pm(hdr->frame_control) &&
+		   (ieee80211_is_data_qos(hdr->frame_control) ||
+		    ieee80211_is_qos_nullfunc(hdr->frame_control))) {
+		tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
+		ac = ieee802_1d_to_ac[tid & 7];
+
+		/*
+		 * If this AC is not trigger-enabled do nothing.
+		 *
+		 * NB: This could/should check a separate bitmap of trigger-
+		 * enabled queues, but for now we only implement uAPSD w/o
+		 * TSPEC changes to the ACs, so they're always the same.
+		 */
+		if (!(rx->sta->sta.uapsd_queues & BIT(ac)))
+			return RX_CONTINUE;
+
+		/* if we are in a service period, do nothing */
+		if (test_sta_flags(rx->sta, WLAN_STA_SP))
+			return RX_CONTINUE;
+
+		if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
+			ieee80211_sta_ps_deliver_uapsd(rx->sta);
+		else
+			set_sta_flags(rx->sta, WLAN_STA_UAPSD);
+	}
+
+	return RX_CONTINUE;
+}
+
 static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 {
@@ -1472,33 +1545,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 	return RX_CONTINUE;
 }
 
-static ieee80211_rx_result debug_noinline
-ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
-{
-	struct ieee80211_sub_if_data *sdata = rx->sdata;
-	__le16 fc = ((struct ieee80211_hdr *)rx->skb->data)->frame_control;
-	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
-
-	if (likely(!rx->sta || !ieee80211_is_pspoll(fc) ||
-		   !(status->rx_flags & IEEE80211_RX_RA_MATCH)))
-		return RX_CONTINUE;
-
-	if ((sdata->vif.type != NL80211_IFTYPE_AP) &&
-	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
-		return RX_DROP_UNUSABLE;
-
-	if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
-		ieee80211_sta_ps_deliver_poll_response(rx->sta);
-	else
-		set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
-
-	/* Free PS Poll skb here instead of returning RX_DROP that would
-	 * count as an dropped frame. */
-	dev_kfree_skb(rx->skb);
-
-	return RX_QUEUED;
-}
-
 static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_remove_qos_control(struct ieee80211_rx_data *rx)
 {
@@ -2567,9 +2613,9 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx)
 
 		CALL_RXH(ieee80211_rx_h_decrypt)
 		CALL_RXH(ieee80211_rx_h_check_more_data)
+		CALL_RXH(ieee80211_rx_h_uapsd_and_pspoll)
 		CALL_RXH(ieee80211_rx_h_sta_process)
 		CALL_RXH(ieee80211_rx_h_defragment)
-		CALL_RXH(ieee80211_rx_h_ps_poll)
 		CALL_RXH(ieee80211_rx_h_michael_mic_verify)
 		/* must be after MMIC verify so header is counted in MPDU mic */
 #ifdef CONFIG_MAC80211_MESH